Method of segregating olefines



pn. i7, E923.

' L. c. STEWART METHOD OF SEGREGATING-OLEFINES Filed Jan. 12, 1920 Sionou w Cm woLmr Patented Apr. 17, 1923.

fuNrrnD. s'rArasgPAraNT OFFICE.

LEROY C. STEWART, 0F MIDLAND, MICHIGAN, ASSIGNOR TO THE DOW CHEMICAL y COMPANY, OIF-MIDLAND, MICHIGAN, A CORPORATION 0F MICHIGAN. I

METHOD OF SEGREGATING OLEFINES.

Application led' January 12, 1920.' Serial No. 350,999.

To'all whom t may concern.:

.Be it known that I, LEROY C. STEWART, a citizen of the United States, and aresident of Midland, [county ot Midland, and State of Michigan, have invented a new and useful Improvement in Methods of Segregating Oleines, of which the following is a specification,-the principle of the invention'being herein explained, and the best mode in which I have contemplated applying ,that principle, so as to distinguish it Afrom other inventions.

VThe production of oleines by cracking kerosene or other petroleum oil, that is by passing it through heated tubes, into heated retorts or similar apparatus, has been known and practiced for sometime. When the temperature in such cracking process is properly regulated, an oil gas can be produced which will contain about ifty per cent of oleines, the remaining fifty per cent consisting of hydrogen, methane and other saturated hydrocarbons; while by varying the cracking conditions, such olefines may be made to consist almost entirely of ethylene, or of only some thirty or forty per cent ethylene, and the balance propylene and other higher members of the, series.l

Oil gas obtained in the manner just described has been found a convenient basis for the production of eth lene or glycol:

. `chlorhydrin (CILOI'LCH, l), as also for the production of other similar chlorine derivatives, such as propylene chlorhydrin (CI-I,.CH,C1.CHOH), but for such use the gas must be quite rich in oleines, that is it is desirable that it contain not more than twenty per cent oimpurities. The present improved method or process has as its object the segregation of the higher olenes, i. e. those above ethylene in the series, so

A that the chlorh drins may be correspondingly segregate ,'or rather be entirely separately made.

To the accomplishmentV of the foregoing and relatedends, the invention, then,- con-' sists of the ste s hereinafter fully described and particular y .pointed out in the claims, the annexed drawing and the following description setting forth in detail certain means and one mode of carrying out the invention, such disclosed means and inodeV illustrating, however, but one of lvarious ways in which the principle of the invention may be used.

In said annexed drawing The single figure thereappearing represents diagrammatically an apparatus suitable for carrying out my improved process.

Such process 1s based on the wholly unl en ected discovery that certain oils and spec1 cally kerosene, will absorb propylene more readily than ethylene so that by washying an oil gas of the character in question with cold kerosene, for -an example, in an amount that would be more than saturated if it absorbed or dissolved all 'of the olefines in the gasffmixture, there will be a tendency for the kerosene to take up more propylene than ethylene. In this Way, accordingly, by a series of washings with such kerosene in properly regulated amount, such propylene and related higher oleines may be satisfactorily separated, for all practical purposes, from ethylene and the other constituents of the gas.v A certain amount of saturated hydrocarbons, such as butane, pen.- tane, hexane, etc., will remain with the propylene lfraction, but the separation is very good, giving a propylene Whichcan be used at once for making chlorhydrin.,v The ethy-r series of coke filled scrubbing towers .1, 2, 3, 4, with heaters l, 2, 3, 4,respect1vely.

connected to receive the absorbing .liquor from each such tower. Means comprlsmg a reservoir 5, pum-p 6, and suitable connections 7 8 and 9, are adapted tocirculate such liquor through such towers and connected 100 heaters in parallel. A cooler 10 is desirably inserted in such connection 9 sc as to reduce the temperature of the\c1rculat1ng liquor to the propcr degree before it is returnedto 11 reservolr. t v

Thegoilgas, i. e. the gas' received from the furnace or retort in which the kerosene or other petroleum oil is cracked, is conducted by means of pipes 11 and 12 through towers Oli 1 and 2 in series, the residual gas being dis- 110 charged from such last mentioned tower i, through a vent pipe 13. Heater 2, connected with the second of the series of towers through which the oil gas is thus passed against a counter-current of scrubbing liquor, specifically kerosene, is connected by means of a pipe 14 with pipe 11, so that the gas driven off from the erosene passing through such heater is continuously returned to be rescrubbed in tower 1. Heater 1,a on the contrary, is connected by means of a pipe 15 with tower 3, so that the gas given oi therefrom is scrubbed in this tower, the residue after such scrubbing being returned by means of pipe 16 to the bottom of tower 1 where it joins the incoming oil gas and the gas driven o, as just stated, from heater 2a.

The gas driven of'f from heater da is conducted by means of pipe 17 to tower 4, the unabsorbed residue being returned by means of pipe 18 to tower 3 where it joins the gas driven ofi, as previously described, from I heater 1a.

The' gas which is absorbed by the kerosene in such final tower 4 of the series, consists practically entirely of propylene and related higher olefines, so that when the kerosene from this tower is passed throughl heater 4a, the gas driven ofi therefrom through discharge duct 20 constitutes the final purified product.

rl`he general operation of the apparatus just described has been sufiiciently indicated in the description of the construction and arrangement of such apparatus. By means of the connections shown, the propylene fraction initially separated out is, it will be seen, subjected to repeated scrubbings,

only the gas that is absorbed following the last such scrubbing being included in the final product. The residual gas passing` out through duct 13 will similarly be seen to consist of the residue left over after successive scrubbings of the original oil gas, as Vintroduced into the system, and of the gas -absorbed in the first towers of the system after it is subsequently driven od' in the corresponding heaters connected with said towers. The result is that the propylene fraction is practically completely segregated from the ethylene, so that these respective constituents of the original oil gas may be utilized in subsequent manufacturing operations, without the presence of the one interfering with the reactions it is desired to secure in the other. Thus for example I am enabled, by means of the present process, to obtain a chlorhydrin product from the propylene fraction, which is Substantially` aasaaa the steps stated by any of the following claims or the equivalent of such stated steps be employed.

I- therefore particularly point out and distinctly claim as my invention 1. In a vmethod of segregating olefines from a. gaseous intermixture of the same,

termixture into Contact with a cold petroleum oil capable of absorbing propylene and thc higher members of the series in preterencel to ethylene, whereby such propylene and higher members are separated vfrom such ethylene, substantially as described.

42. ln a method of segregating olefines from a gaseous intermixture of the same, the stepsl which consist in bringing such intermixture into contact with a cold petroleum oil capable of absorbing propylene and the higher members of the series in preference to ethylene and heating such oil to drive ofi' the absorbed gases, consisting of such propylene and higher members, whereby they are obtained separately from such ethylene.

3. In a. method of segregatingolefines from a gaseous intermixture of the same, the step which consists in bringinel such intermixtureinto contact with cold1 kerosene whereby propylene and the higher members of the series are absorbed preferentially to ethylene, substantially as described.

4. ln aV method of segregating oleiines from a gaseous intermixture of the same, the steps which consist in bringing such intermixture' into contact with cold kerosene whereby propylene and thehigher members of the series are absorbed preferentially to ethyleaetand then heating such kerosene to drive o he absorbed gases.

5. n a method of segregatingoletines from a gaseous intermixture of the same, theV steps which consist in scrubbing such lntermlxture with kerosene, thereupon heating such kerosene to drive ofi` the absorbed gases, again scrubbing the. latter with kerosene, and then heating as before.

6. In a method of segregating oleines from a gaseous mixture of the same, the steps which consist in scrubbing such mixture with kerosene, thereupon heating such kerosene to drive 0E the absorbed gases, again scrubbing the latter with kerosene, and then heating as before, the residual `gases from such second scrubbing being added to those in theA first scrubbing.

7. In a method of segregating olenes from a aseous mixture of the same, the steps which consist in scrubbing such mixture with kerosene in a series of steps, heating the kerosene from each-such step to drive oi' the absorbed gases, and adding the gases thusl driven o from thekerosene passing through each subsequent step to those passing through the first Step of the series. Y'

the step which consists in bringing such in-v Y 8. In a method of aggregating olenes from a seous' mixture of the same, the steps which consist in scrubbing such mixture with kerosene in a series of stepsheat ing the kerosene from each such step to drlve off the absorbed gases, adding the gases thus driven ofil from the kerosene passing'A througheach subsequent ste to those passing through the first step o the series, and separately scrubbing the gases thus driven off from the kerosene passing through such first step.

9. In a method of aggregating oleiines from a seous mixture of the same, the

steps which consist in scrubbing such mixture with kerosene in a series of steps, heat,-

in the kerosene from each such step to drive ofi the absorbed gases, adding the gases thus driven of from the kerosene passing through each subsequent step to those passing through the first step -of the series, and

. separately scrubbing the gases thus driven off from the kerosene passing through such,

first step, the residual gases'from such lastmentioned scrubbing being likewise added to those passing through such first step.

each subsequent step to vthose passingthrough the first step of the series, se arately scrubbing the gases thus driven off rom the kerosene passing through such first step, the .i

residual gases from sueh last-mentioned scrubbing being likewise added to those passing through such first step, heating the kerosene passing over such last-mentioned' step,

land re-scrubbing the gases thus driven off.

11. In a method of segregating olenes fromav gaseous mixture kof the same, the steps which consist in scrubbing. such mixture with kerosene in a series of steps, heating the kerosene from each such step to drive -oi the absorbed gases, adding the gases thus driven ofi' from the kerosene passing through each subsequent stepto/'those passing through the first step of the series, separately scrubbing the gases thusdriven off from the kerosene passing through suchfirst step, the residual gases from such last-meni.

tioned` scrubbing being likewise added to those passing through such first step, heating thf kerosene passingo'ver such last-mentioned step, re-scrubbing the gases thus driven off, adding the residual gases to those in the preceding scrubbing, and heating the kerosene from such re-serubbing to driveoff the finally purified gases.

Signed'by me, this 7th day of January, 1920. n

LEROY e. STEWART'. 

